Three isomeric (E)-nitrobenzaldehyde nitrophenylhydrazones:: chains of rings in isomorphous (E)-2-nitrobenzaldehyde 3-nitrophenylhydrazone and (E)-3-nitrobenzaldehyde 2-nitrophenylhydrazone, and centrosymmetric dimers in (E)-4-nitrobenzaldehyde 2-nitrophenylhydrazone

The isomeric compounds (E)-2-nitrobenzaldehyde 3-nitrophenylhydrazone and (E)-3-nitrobenzaldehyde 2-nitrophenylhydrazone, both C13H10N4O4, are isomorphous and effectively isostructural, and in both, the molecules are disordered across centres of inversion in the space group P2(1)/c. The molecules are linked into complex chains of rings by N-H center dot center dot center dot O and C-H center dot center dot center dot O hydrogen bonds. In the isomeric compound (E)-4-nitrobenzaldehyde 2-nitrophenylhydrazone, the fully ordered molecules are linked by N-H center dot center dot center dot O hydrogen bonds into centrosymmetric dimers.